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Zeider K, Manjón I, Betterton EA, Sáez AE, Sorooshian A, Ramírez-Andreotta MD. Backyard aerosol pollution monitors: foliar surfaces, dust enrichment, and factors influencing foliar retention. Environ Monit Assess 2023; 195:1200. [PMID: 37700111 PMCID: PMC10636967 DOI: 10.1007/s10661-023-11752-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 08/19/2023] [Indexed: 09/14/2023]
Abstract
Air pollution is one of the leading causes of death from noncommunicable diseases globally, and in Arizona, both mining activities and abandoned agriculture can generate erodible dust. This dust is transported via wind and can carry high amounts of toxic pollutants. Industry-adjacent communities, or "fenceline communities," are generally closer to the pollution sources and are disproportionally impacted by pollution, or in this case, dust. The dust transported from the mine settles into nearby rivers, gardens, and homes, and increases the concentrations of elements beyond their naturally occurring amounts (i.e., enriched). This study was built upon previous community science work in which plant leaves were observed to collect similar concentrations to an accepted dust collection method and illustrated promise for their use as low-cost air quality monitors in these communities. This work investigated the concentration of Na, Mg, Al, K, Ca, Mn, Co, Cu, Zn, Mo, and Ba in dust from the leaves of community-collected backyard and garden plants (foliar dust), as well as if certain variables affected collection efficacy. This assessment evaluated (1) foliar concentration versus surface area for 11 elements, (2) enrichment factor (EF) values and ratios, (3) comparisons of foliar, garden, and yard samples to US Geological Survey data, and (4) what variable significantly affected dust collection efficacy. The EF results indicate that many of the samples were enriched (anthropogenically contaminated) and that the foliar samples were generally more contaminated than the yard and garden soil samples. Leaf surface area was the most influential factor for leaf collection efficiency (p < 0.05) compared to plant family or sampling location. Further studies are needed that standardize the plant species and age and include multiple replicates of the same plant species across partnering communities. This study has demonstrated that foliar dust is enriched in the participating partnering communities and that plant leaf samples can serve as backyard aerosol pollution monitors. Therefore, foliar dust is a viable indicator of outdoor settled dust and aerosol contamination and this is an adoptable monitoring technique for "fenceline communities."
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Affiliation(s)
- Kira Zeider
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Iliana Manjón
- Department of Environmental Science, University of Arizona, Tucson, AZ, USA
| | - Eric A Betterton
- Department of Hydrology and Atmospheric Sciences, University of Arizona, 1177 E Fourth Street, Rm. 429, Tucson, AZ, 85721, USA
| | - A Eduardo Sáez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Armin Sorooshian
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
- Department of Hydrology and Atmospheric Sciences, University of Arizona, 1177 E Fourth Street, Rm. 429, Tucson, AZ, 85721, USA
| | - Mónica D Ramírez-Andreotta
- Department of Environmental Science, University of Arizona, Tucson, AZ, USA.
- Mel and Enid Zuckerman College of Public Health's Division of Community, Environment & Policy, University of Arizona, Tucson, AZ, USA.
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Zeider K, Van Overmeiren N, Rine KP, Sandhaus S, Eduardo Sáez A, Sorooshian A, Muñoz HC, Ramírez-Andreotta MD. Foliar surfaces as dust and aerosol pollution monitors: An assessment by a mining site. Sci Total Environ 2021; 790:148164. [PMID: 34380246 PMCID: PMC8362843 DOI: 10.1016/j.scitotenv.2021.148164] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 05/21/2021] [Accepted: 05/27/2021] [Indexed: 05/09/2023]
Abstract
Recent studies in the southwestern United States have shown that smelting processes and mine tailings emit heavy metal(loid)s that are distributed via wind dispersion to nearby communities. With increased attention regarding the effect of air pollution on environmental health, communities have begun to use citizen/community-based monitoring techniques to measure the concentration of metal(loid)s and evaluate their air quality. This study was conducted in a mining community to assess the efficacy of foliar surfaces as compared to an inverted disc (frisbee) to sample aerosol pollutants in ambient air. The assessment was conducted by evaluating As, Pb, Cd, Cu, Al, Ni, and Zn concentrations versus distance from a former smelter, statistical and regression analyses, and enrichment factor calculations compared to similar sites worldwide. Both the foliar and frisbee collection methods had a decrease in metal(loid)s concentration as a function of distance from the retired smelter. Statistical calculations show that the collection methods had similar mean concentrations for all of the metal(loid)s of interest; however, the tests also indicate that the frisbee collection method generally collected more dust than the foliar method. The enrichment factors from both collection methods were comparable to similar studies by other mining areas referenced, except for aluminum. Since there is evidence of enrichment, correlation between methods, and citizen/community science potential, these efforts show promise for the field. Further studies should consider alternating the types of plant used for foliar collection as well as collecting samples on a more frequent basis in order to sufficiently categorize results based on meteorological conditions.
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Affiliation(s)
- Kira Zeider
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Nicole Van Overmeiren
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Kyle P Rine
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
| | - Shana Sandhaus
- Department of Environmental Science, University of Arizona, Tucson, AZ, USA
| | - A Eduardo Sáez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Armin Sorooshian
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA; Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
| | - Henry C Muñoz
- Concerned Citizens and Retired Miners Coalition of Superior, AZ, USA
| | - Mónica D Ramírez-Andreotta
- Department of Environmental Science, University of Arizona, Tucson, AZ, USA; Mel and Enid Zuckerman College of Public Health's Division of Community, Environment & Policy, University of Arizona, Tucson, AZ, USA.
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Heusinkveld D, Ramirez-Andreotta MD, Rodríguez-Chávez T, Sáez AE, Betterton E, Rine K. Assessing Children's Lead Exposure in an Active Mining Community Using the Integrated Exposure Uptake Biokinetic Model. Expo Health 2021; 13:517-533. [PMID: 34532608 PMCID: PMC8439183 DOI: 10.1007/s12403-021-00400-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Lead exposure has been shown to be harmful to humans in various settings and there are no safe levels of blood lead in children. At an Alternative Superfund site in Hayden-Winkelman, Arizona, with an active copper smelter and concentrator, lead exceedances in air and soil have been measured in the past 20 years. In this work, the U.S. Environmental Protection Agency's Integrated Exposure Uptake Biokinetic (IEUBK) model was used to estimate Hayden-Winkelman children's (age 6 months-7 years) blood lead levels (BLLs) using site-specific lead concentrations measured in indoor and outdoor air, soil, indoor dust, and drinking water. Values used by a state agency's airborne lead risk forecast program were also evaluated to determine whether their forecasting program is useful in protecting children's public health. Using site-specific values in the model, the results demonstrated that lead ingested via indoor dust was the major contributor to children's BLLs. In addition, the output of the IEUBK model overestimated actual BLLs of children sampled in the community. The IEUBK model was particularly sensitive to high indoor dust levels, and these site-specific measures increased modeled BLL values. This finding is of significance as the IEUBK model is used worldwide in communities with industrial contamination. This study confirmed that the chief contributor to lead exposure in children is household dust. Thus, for lead exposure risk reduction, agencies working at Superfund sites should focus efforts on decontaminating outdoor soil and dust and indoor lead decontamination.
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Affiliation(s)
| | - Mónica D. Ramirez-Andreotta
- Department of Environmental Science, University of Arizona
- Mel and Enid Zuckerman College of Public Health’s Division of Community, Environment & Policy, University of Arizona
- Corresponding Author: Mónica Ramírez-Andreotta, M.P.A, Ph.D., 1177 E Fourth Street, Rm. 429, Tucson, AZ 85721, Phone: 520-621-0091; Fax: 520-621-1647,
| | | | - A. Eduardo Sáez
- Department of Chemical and Environmental Engineering, University of Arizona
| | - Eric Betterton
- Department of Atmospheric Sciences, University of Arizona
| | - Kyle Rine
- Department of Chemical and Environmental Engineering, University of Arizona
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Niu XZ, Pepel RD, Paniego R, Field JA, Chorover J, Abrell L, Sáez AE, Sierra-Alvarez R. Photochemical fate of sulfonium photoacid generator cations under photolithography relevant UV irradiation. J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2021.113324] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Manjón I, Ramírez-Andreotta MD, Sáez AE, Root RA, Hild J, Janes MK, Alexander-Ozinskas A. Ingestion and inhalation of metal(loid)s through preschool gardening: An exposure and risk assessment in legacy mining communities. Sci Total Environ 2020; 718:134639. [PMID: 31843310 PMCID: PMC7176541 DOI: 10.1016/j.scitotenv.2019.134639] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/21/2019] [Accepted: 09/23/2019] [Indexed: 05/09/2023]
Abstract
Children residing in mining towns are potentially disproportionately exposed to metal(loid)s via ingestion and dust inhalation, thus, increasing their exposure when engaging in school or home gardening or playing outside. This citizen science study assessed preschool children's potential arsenic (As), cadmium (Cd), and lead (Pb) exposure via locally grown produce, water, incidental soil ingestion, and dust inhalation at four sites. Participants were trained to properly collect water, soil, and vegetable samples from their preschools in Nevada County, California. As, Cd, and Pb concentrations in irrigation sources did not exceed the U.S. EPA's maximum contaminant and action levels. In general, garden and playground As and Pb soil concentrations exceeded the U.S. EPA Regional Screening Level, CalEPA Human Health Screening Level, and California Department of Toxic Substances Control Screening Level. In contrast, all Cd concentrations were below these recommended screening levels. Dust samples (<10 μm diameter) were generated from surface garden and playground soil collected at the preschools by a technique that simulated windblown dust. Soil and dust samples were then analyzed by in-vitro bioaccessibility assays using synthetic lung and gastric fluids to estimate the bioaccessible fraction of As, Cd, and Pb in the body. Metal(loid) exposure via grown produce revealed that lettuce, carrot, and cabbage grown in the preschool gardens accumulated a higher concentration of metal(loid) than those store-bought nation-wide. None of the vegetables exceeded the respective recommendation maximum levels for Cd and Pb set by the World Health Organization Codex Alimentarius Commission. The results of this study indicate that consumption of preschool-grown produce and incidental soil ingestion were major contributors to preschool-aged children's exposure to As, Cd, and Pb. Traditionally, this level of site- and age-specific assessment and analyses does not occur at contaminated sites. The results of this holistic risk assessment can inform future risk assessment and public health interventions related to childhood metal(loid) exposures.
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Affiliation(s)
- Iliana Manjón
- Department of Soil, Water, and Environmental Science, University of Arizona, Tucson, AZ, United States
| | - Mónica D Ramírez-Andreotta
- Department of Soil, Water, and Environmental Science, University of Arizona, Tucson, AZ, United States; Mel and Enid Zuckerman College of Public Health's Division of Community, Environment & Policy, University of Arizona, Tucson, AZ, United States.
| | - A Eduardo Sáez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, United States
| | - Robert A Root
- Department of Soil, Water, and Environmental Science, University of Arizona, Tucson, AZ, United States
| | - Joanne Hild
- Sierra Streams Institute, Nevada City, CA, United States
| | - M Katy Janes
- California Department of Water Resources, Sacramento, CA, United States
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6
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Manjón I, Ramírez-Andreotta MD, Sáez AE, Root RA, Hild J, Janes MK, Alexander-Ozinskas A. Environmental monitoring and exposure science dataset to calculate ingestion and inhalation of metal(loid)s through preschool gardening. Data Brief 2020; 29:105050. [PMID: 32055651 PMCID: PMC7005369 DOI: 10.1016/j.dib.2019.105050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 12/17/2019] [Indexed: 11/17/2022] Open
Abstract
Metal(loid) contamination may pose an increased risk of exposure to children residing near legacy and active resource extraction sites. Children may be exposed to arsenic, cadmium, and/or lead by ingestion and/or inhalation while engaging in school or home outdoor activities via environmental media including water, soil, dust, and locally grown produce. It is thus critical to collect site-specific data to best assess these risks. This data article provides gastric and lung in-vitro bioaccessibility assay (IVBA) data, as well as environmental monitoring data for water, soil, dust, and garden produce collected from preschools (N = 4) in mining communities throughout Nevada County, California in 2018. Arsenic, cadmium, and lead concentrations in the aforementioned media and synthetic gastric and lung fluids were measured by inductively coupled plasma-mass spectrometry (ICP-MS). This dataset provides useful metal(loid) concentrations for future risk assessments for similar settings.
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Affiliation(s)
- Iliana Manjón
- Department of Environmental Science, University of Arizona, Tucson, AZ, USA
- University of Arizona College of Medicine – Tucson, Tucson, AZ, USA
| | - Mónica D. Ramírez-Andreotta
- Department of Environmental Science, University of Arizona, Tucson, AZ, USA
- Mel and Enid Zuckerman College of Public Health's Division of Community, Environment & Policy, University of Arizona, Tucson, AZ, USA
- Corresponding author. Department of Environmental Science, University of Arizona, Tucson, AZ, USA.
| | - A. Eduardo Sáez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Robert A. Root
- Department of Environmental Science, University of Arizona, Tucson, AZ, USA
| | - Joanne Hild
- Sierra Streams Institute, Nevada City, CA, USA
| | - M. Katy Janes
- California Department of Water Resources, Sacramento, CA, USA
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7
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Gil-Loaiza J, Field JP, White SA, Csavina J, Felix O, Betterton EA, Sáez AE, Maier RM. Phytoremediation Reduces Dust Emissions from Metal(loid)-Contaminated Mine Tailings. Environ Sci Technol 2018; 52:5851-5858. [PMID: 29701964 PMCID: PMC7025808 DOI: 10.1021/acs.est.7b05730] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Environmental and health risk concerns relating to airborne particles from mining operations have focused primarily on smelting activities. However, there are only three active copper smelters and less than a dozen smelters for other metals compared to an estimated 500000 abandoned and unreclaimed hard rock mine tailings in the US that have the potential to generate dust. The problem can also extend to modern tailings impoundments, which may take decades to build and remain barren for the duration before subsequent reclamation. We examined the impact of vegetation cover and irrigation on dust emissions and metal(loid) transport from mine tailings during a phytoremediation field trial at the Iron King Mine and Humboldt Smelter Superfund (IKMHSS) site. Measurements of horizontal dust flux following phytoremediation reveals that vegetated plots with 16% and 32% canopy cover enabled an average dust deposition of 371.7 and 606.1 g m-2 y-1, respectively, in comparison to the control treatment which emitted dust at an average rate of 2323 g m-2 y-1. Horizontal dust flux and dust emissions from the vegetated field plots are comparable to emission rates in undisturbed grasslands. Further, phytoremediation was effective at reducing the concentration of fine particulates, including PM1, PM2.5, and PM4, which represent the airborne particulates with the greatest health risks and the greatest potential for long-distance transport. This study demonstrates that phytoremediation can substantially decrease dust emissions as well as the transport of windblown contaminants from mine tailings.
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Affiliation(s)
- Juliana Gil-Loaiza
- University of Arizona, Department of Soil- Water and Environmental Science, Tucson, AZ 85721, USA
| | - Jason P. Field
- University of Arizona, School of Natural Resources and the Environment, Tucson- AZ 85721, USA
| | - Scott A. White
- University of Arizona, Department of Soil- Water and Environmental Science, Tucson, AZ 85721, USA
| | - Janae Csavina
- University of Arizona, Department of Hydrology and Atmospheric Sciences, Tucson- AZ 85721, USA
| | - Omar Felix
- University of Arizona, Department of Chemical and Environmental Engineering, Tucson- AZ 85721, USA
| | - Eric A. Betterton
- University of Arizona, Department of Hydrology and Atmospheric Sciences, Tucson- AZ 85721, USA
| | - A. Eduardo Sáez
- University of Arizona, Department of Chemical and Environmental Engineering, Tucson- AZ 85721, USA
| | - Raina M. Maier
- University of Arizona, Department of Soil- Water and Environmental Science, Tucson, AZ 85721, USA
- Corresponding author: Raina M. Maier, Department of Soil, Water, and Environmental Science, 1177 E. 4 Street, University of Arizona, Tucson, AZ 85721-0038, , Phone: 520-621-7231, Fax: 520-626-6782
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8
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Thomas AN, Root RA, Lantz RC, Sáez AE, Chorover J. Oxidative weathering decreases bioaccessibility of toxic metal(loid)s in PM 10 emissions from sulfide mine tailings. Geohealth 2018; 2:118-138. [PMID: 30338309 PMCID: PMC6191178 DOI: 10.1002/2017gh000118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Environmental contamination from legacy mine-waste deposits is a persistent problem due to the long history of hard-rock mining. Sulfide ore deposits can contain elevated levels of toxic metal(loid)s that, when mobilized by weathering upon O2 and H2O infusion, can result in groundwater contamination. Dry-climate and lack of vegetative cover result in near-surface pedogenic processes that produce fine-particulate secondary minerals that can be translocated as geo-dusts leading to ingestion or inhalation exposure in nearby communities. In this study, in vitro bioassays were combined with synchrotron-based x-ray spectroscopy and diffraction to determine the potential risk for toxic element release from dust (PM10) samples into biofluid simulants. PM10 were isolated from across the oxidative reaction front in the top meter of tailings subjected to 50 years of weathering under semi-arid climate, and introduced to synthetic gastric- and alveolar-fluids. Aqueous concentrations were measured as a function of reaction time to determine release kinetics. X-ray diffraction and absorption spectroscopy analyses were performed to assess associated changes in mineralogy and elemental speciation. In vitro bioaccessibility of arsenic and lead was highest in less-weathered tailings samples (80-110 cm) and lowest in samples from the sub-oxic transition zone (40-52 cm). Conversely, zinc release to biofluids was greatest in the highly-weathered near-surface tailings. Results indicate that bioaccessibility of As and Pb was controlled by (i) the solubility of Fe2+-bearing solids, (ii) the prevalence of soluble SO4 2-, and (iii) the presence of poorly-crystalline Fe(III) oxide sorbents, whereas Zn bioaccessibility was controlled by the pH-dependent solubility of the stable solid phase.
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Affiliation(s)
- Andrew N. Thomas
- Department of Soil, Water and Environmental ScienceUniversity of ArizonaTucsonAZUSA
| | - Robert A. Root
- Department of Soil, Water and Environmental ScienceUniversity of ArizonaTucsonAZUSA
| | - R. Clark Lantz
- Department of Cellular and Molecular MedicineUniversity of ArizonaTucsonAZUSA
| | - A. Eduardo Sáez
- Department of Chemical and Environmental EngineeringUniversity of ArizonaTucsonAZUSA
| | - Jon Chorover
- Department of Soil, Water and Environmental ScienceUniversity of ArizonaTucsonAZUSA
- Arizona Laboratory for Emerging ContaminantsUniversity of ArizonaTucsonAZUSA
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Karanikola V, Corral AF, Jiang H, Sáez AE, Ela WP, Arnold RG. Effects of membrane structure and operational variables on membrane distillation performance. J Memb Sci 2017. [DOI: 10.1016/j.memsci.2016.11.038] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Youn JS, Csavina J, Rine KP, Shingler T, Taylor MP, Sáez AE, Betterton EA, Sorooshian A. Hygroscopic Properties and Respiratory System Deposition Behavior of Particulate Matter Emitted By Mining and Smelting Operations. Environ Sci Technol 2016; 50:11706-11713. [PMID: 27700056 PMCID: PMC5089925 DOI: 10.1021/acs.est.6b03621] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
This study examines size-resolved physicochemical data for particles sampled near mining and smelting operations and a background urban site in Arizona with a focus on how hygroscopic growth impacts particle deposition behavior. Particles with aerodynamic diameters between 0.056-18 μm were collected at three sites: (i) an active smelter operation in Hayden, AZ, (ii) a legacy mining site with extensive mine tailings in Iron King, AZ, and (iii) an urban site, inner-city Tucson, AZ. Mass size distributions of As and Pb exhibit bimodal profiles with a dominant peak between 0.32 and 0.56 μm and a smaller mode in the coarse range (>3 μm). The hygroscopicity profile did not exhibit the same peaks owing to dependence on other chemical constituents. Submicrometer particles were generally more hygroscopic than supermicrometer ones at all three sites with finite water-uptake ability at all sites and particle sizes examined. Model calculations at a relative humidity of 99.5% reveal significant respiratory system particle deposition enhancements at sizes with the largest concentrations of toxic contaminants. Between dry diameters of 0.32 and 0.56 μm, for instance, ICRP and MPPD models predict deposition fraction enhancements of 171%-261% and 33%-63%, respectively, at the three sites.
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Affiliation(s)
- Jong-sang Youn
- Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA
| | - Janae Csavina
- National Ecological Observatory Network (NEON), 1685 38 Street, Boulder, CO USA
| | - Kyle P. Rine
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
| | - Taylor Shingler
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Mark Patrick Taylor
- Department of Environmental Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
| | - A. Eduardo Sáez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Eric A. Betterton
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
| | - Armin Sorooshian
- Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
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11
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Zhang T, Cheng L, Ma L, Meng F, Arnold RG, Sáez AE. Modeling the oxidation of phenolic compounds by hydrogen peroxide photolysis. Chemosphere 2016; 161:349-357. [PMID: 27448315 DOI: 10.1016/j.chemosphere.2016.06.110] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 06/13/2016] [Accepted: 06/29/2016] [Indexed: 06/06/2023]
Abstract
Hydrogen peroxide UV photolysis is among the most widely used advanced oxidation processes (AOPs) for the destruction of trace organics in waters destined for reuse. Previous kinetic models of hydrogen peroxide photolysis focus on the dynamics of hydroxyl radical production and consumption, as well as the reaction of the target organic with hydroxyl radicals. However, the rate of target destruction may also be affected by radical scavenging by reaction products. In this work, we build a predictive kinetic model for the destruction of p-cresol by hydrogen peroxide photolysis based on a complete reaction mechanism that includes reactions of intermediates with hydroxyl radicals. The results show that development of a predictive kinetic model to evaluate process performance requires consideration of the complete reaction mechanism, including reactions of intermediates with hydroxyl radicals.
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Affiliation(s)
- Tianqi Zhang
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, 85721, United States
| | - Long Cheng
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, 85721, United States
| | - Lin Ma
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, 85721, United States
| | - Fanchao Meng
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, 85721, United States
| | - Robert G Arnold
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, 85721, United States
| | - A Eduardo Sáez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, 85721, United States.
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12
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Guzmán HM, Li J, Keshta M, Sáez AE, Ela WP. Release of arsenic from metal oxide sorbents under simulated mature landfill conditions. Chemosphere 2016; 151:84-93. [PMID: 26928334 DOI: 10.1016/j.chemosphere.2016.02.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 01/08/2016] [Accepted: 02/09/2016] [Indexed: 06/05/2023]
Affiliation(s)
- Héctor M Guzmán
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA.
| | - Jing Li
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA.
| | - Mohammed Keshta
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA.
| | - A Eduardo Sáez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA.
| | - Wendell P Ela
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA; School of Engineering and Information Technology, Murdoch University, Murdoch, 6150, WA, Australia.
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Landázuri AC, Sáez AE, Anthony TR. Three-dimensional computational fluid dynamics modeling of particle uptake by an occupational air sampler using manually-scaled and adaptive grids. J Aerosol Sci 2016; 95:54-66. [PMID: 26949268 PMCID: PMC4774053 DOI: 10.1016/j.jaerosci.2016.01.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This work presents fluid flow and particle trajectory simulation studies to determine the aspiration efficiency of a horizontally oriented occupational air sampler using computational fluid dynamics (CFD). Grid adaption and manual scaling of the grids were applied to two sampler prototypes based on a 37-mm cassette. The standard k-ε model was used to simulate the turbulent air flow and a second order streamline-upwind discretization scheme was used to stabilize convective terms of the Navier-Stokes equations. Successively scaled grids for each configuration were created manually and by means of grid adaption using the velocity gradient in the main flow direction. Solutions were verified to assess iterative convergence, grid independence and monotonic convergence. Particle aspiration efficiencies determined for both prototype samplers were undistinguishable, indicating that the porous filter does not play a noticeable role in particle aspiration. Results conclude that grid adaption is a powerful tool that allows to refine specific regions that require lots of detail and therefore better resolve flow detail. It was verified that adaptive grids provided a higher number of locations with monotonic convergence than the manual grids and required the least computational effort.
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Affiliation(s)
- Andrea C Landázuri
- The University of Arizona, Department of Chemical and Environmental Engineering, 1133 E James E. Rogers Way, Tucson, AZ 85641, United States; Universidad San Francisco de Quito USFQ, Colegio de Ciencias e Ingenierías "El Politécnico", Departamento de Ingeniería Química, Calle Diego de Robles y Vía Interoceánica, Cumbayá, Casilla Postal: 17-1200-841, Quito, Ecuador
| | - A Eduardo Sáez
- The University of Arizona, Department of Chemical and Environmental Engineering, 1133 E James E. Rogers Way, Tucson, AZ 85641, United States
| | - T Renée Anthony
- The University of Iowa, Department of Occupational and Environmental Health, 145 N. Riverside Drive, S300, Iowa City, IA 52242-5000, United States
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14
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Wang H, Cheng L, Sáez AE, Pemberton JE. Flow Field Penetration in Thin Nanoporous Polymer Films under Laminar Flow by Förster Resonance Energy Transfer Coupled with Total Internal Reflectance Fluorescence Microscopy. Anal Chem 2015; 87:11746-54. [DOI: 10.1021/acs.analchem.5b03751] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Huan Wang
- Department of Chemistry and Biochemistry and ‡Department of
Chemical and Environmental
Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Long Cheng
- Department of Chemistry and Biochemistry and ‡Department of
Chemical and Environmental
Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - A. Eduardo Sáez
- Department of Chemistry and Biochemistry and ‡Department of
Chemical and Environmental
Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Jeanne E. Pemberton
- Department of Chemistry and Biochemistry and ‡Department of
Chemical and Environmental
Engineering, University of Arizona, Tucson, Arizona 85721, United States
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15
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Dong B, Kahl A, Cheng L, Vo H, Ruehl S, Zhang T, Snyder S, Sáez AE, Quanrud D, Arnold RG. Fate of trace organics in a wastewater effluent dependent stream. Sci Total Environ 2015; 518-519:479-490. [PMID: 25777953 DOI: 10.1016/j.scitotenv.2015.02.074] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/22/2015] [Accepted: 02/22/2015] [Indexed: 06/04/2023]
Abstract
Trace organic compounds (TOrCs) in municipal wastewater effluents that are discharged to streams are of potential concern to ecosystem and human health. This study examined the fate of a suite of TOrCs and estrogenic activity in water and sediments in an effluent-dependent stream in Tucson, Arizona. Sampling campaigns were performed during 2011 to 2013 along the Lower Santa Cruz River, where TOrCs and estrogenic activity were measured in aqueous (surface) and solid (riverbed sediment) phases. Some TOrCs, including contributors to estrogenic activity, were rapidly attenuated with distance of travel in the river. Those TOrCs that are not sufficiently attenuated and percolate to ground water have in common low biodegradation probabilities and low octanol-water distribution ratios. Independent experiments showed that attenuation of estrogenic compounds may be due in part to indirect photolysis caused by formation of organic radicals from sunlight absorption. Hydrophobic TOrCs may accumulate in riverbed sediments during dry weather periods, but riverbed sediment quality is periodically affected through storm-related scouring during periods of heavy rainfall and runoff. Taken together, evidence suggests that natural processes can attenuate at least some TOrCs, reducing potential impacts to ecosystem and human health.
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Affiliation(s)
- Bingfeng Dong
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA
| | - Alandra Kahl
- Penn State Greater Allegheny, Pennsylvania State University, McKeesport, PA 15132, USA
| | - Long Cheng
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA
| | - Hao Vo
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA
| | - Stephanie Ruehl
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA
| | - Tianqi Zhang
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA
| | - Shane Snyder
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA
| | - A Eduardo Sáez
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA
| | - David Quanrud
- School of Natural Resources and the Environment, The University of Arizona, Tucson, AZ 85721, USA.
| | - Robert G Arnold
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA
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16
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Karanikola V, Corral AF, Jiang H, Eduardo Sáez A, Ela WP, Arnold RG. Sweeping gas membrane distillation: Numerical simulation of mass and heat transfer in a hollow fiber membrane module. J Memb Sci 2015. [DOI: 10.1016/j.memsci.2015.02.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Félix OI, Csavina J, Field J, Rine KP, Sáez AE, Betterton EA. Use of lead isotopes to identify sources of metal and metalloid contaminants in atmospheric aerosol from mining operations. Chemosphere 2015; 122:219-226. [PMID: 25496740 PMCID: PMC4277909 DOI: 10.1016/j.chemosphere.2014.11.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 11/07/2014] [Accepted: 11/18/2014] [Indexed: 05/13/2023]
Abstract
Mining operations are a potential source of metal and metalloid contamination by atmospheric particulate generated from smelting activities, as well as from erosion of mine tailings. In this work, we show how lead isotopes can be used for source apportionment of metal and metalloid contaminants from the site of an active copper mine. Analysis of atmospheric aerosol shows two distinct isotopic signatures: one prevalent in fine particles (<1μm aerodynamic diameter) while the other corresponds to coarse particles as well as particles in all size ranges from a nearby urban environment. The lead isotopic ratios found in the fine particles are equal to those of the mine that provides the ore to the smelter. Topsoil samples at the mining site show concentrations of Pb and As decreasing with distance from the smelter. Isotopic ratios for the sample closest to the smelter (650m) and from topsoil at all sample locations, extending to more than 1km from the smelter, were similar to those found in fine particles in atmospheric dust. The results validate the use of lead isotope signatures for source apportionment of metal and metalloid contaminants transported by atmospheric particulate.
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Affiliation(s)
- Omar I Félix
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Janae Csavina
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - Jason Field
- Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
| | - Kyle P Rine
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - A Eduardo Sáez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA.
| | - Eric A Betterton
- Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
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18
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Gonzales P, Felix O, Alexander C, Lutz E, Ela W, Eduardo Sáez A. Laboratory dust generation and size-dependent characterization of metal and metalloid-contaminated mine tailings deposits. J Hazard Mater 2014; 280:619-26. [PMID: 25222928 DOI: 10.1016/j.jhazmat.2014.09.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/06/2014] [Accepted: 09/01/2014] [Indexed: 05/24/2023]
Abstract
The particle size distribution of mine tailings material has a major impact on the atmospheric transport of metal and metalloid contaminants by dust. Implications to human health should be assessed through a holistic size-resolved characterization involving multidisciplinary research, which requires large uniform samples of dust that are difficult to collect using conventional atmospheric sampling instruments. To address this limitation, we designed a laboratory dust generation and fractionation system capable of producing several grams of dust from bulk materials. The equipment was utilized in the characterization of tailings deposits from the arsenic and lead-contaminated Iron King Superfund site in Dewey-Humboldt, Arizona. Results show that metal and metalloid contaminants are more concentrated in particles of < 10 μm aerodynamic diameter, which are likely to affect surrounding communities and ecosystems. In addition, we traced the transport of contaminated particles from the tailings to surrounding soils by identifying Pb and Sr isotopic signatures in soil samples. The equipment and methods developed for this assessment ensure uniform samples for further multidisciplinary studies, thus providing a tool for comprehensive representation of emission sources and associated risks of exposure.
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Affiliation(s)
- Patricia Gonzales
- Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721, USA
| | - Omar Felix
- Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721, USA
| | - Caitlin Alexander
- Division of Community, Environment, and Policy, Mel & Enid Zuckerman College of Public Health, University of Arizona, 1656 E. Mabel St., Tucson, AZ 85724, USA
| | - Eric Lutz
- Division of Community, Environment, and Policy, Mel & Enid Zuckerman College of Public Health, University of Arizona, 1656 E. Mabel St., Tucson, AZ 85724, USA
| | - Wendell Ela
- Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721, USA
| | - A Eduardo Sáez
- Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Tucson, AZ 85721, USA.
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19
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Csavina J, Taylor MP, Félix O, Rine KP, Eduardo Sáez A, Betterton EA. Size-resolved dust and aerosol contaminants associated with copper and lead smelting emissions: implications for emission management and human health. Sci Total Environ 2014; 493:750-6. [PMID: 24995641 PMCID: PMC4137906 DOI: 10.1016/j.scitotenv.2014.06.031] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 05/29/2014] [Accepted: 06/10/2014] [Indexed: 04/13/2023]
Abstract
Mining operations, including crushing, grinding, smelting, refining, and tailings management, are a significant source of airborne metal and metalloid contaminants such as As, Pb and other potentially toxic elements. In this work, we show that size-resolved concentrations of As and Pb generally follow a bimodal distribution with the majority of contaminants in the fine size fraction (<1 μm) around mining activities that include smelting operations at various sites in Australia and Arizona. This evidence suggests that contaminated fine particles (<1 μm) are the result of vapor condensation and coagulation from smelting operations while coarse particles are most likely the result of windblown dust from contaminated mine tailings and fugitive emissions from crushing and grinding activities. These results on the size distribution of contaminants around mining operations are reported to demonstrate the ubiquitous nature of this phenomenon so that more effective emission management and practices that minimize health risks associated with metal extraction and processing can be developed.
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Affiliation(s)
- Janae Csavina
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA
| | - Mark P Taylor
- Environmental Science, Faculty of Science, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
| | - Omar Félix
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA
| | - Kyle P Rine
- Department of Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721, USA
| | - A Eduardo Sáez
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA.
| | - Eric A Betterton
- Department of Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721, USA.
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20
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Stovern M, Felix O, Csavina J, Rine KP, Russell MR, Jones RM, King M, Betterton EA, Sáez AE. Simulation of windblown dust transport from a mine tailings impoundment using a computational fluid dynamics model. Aeolian Res 2014; 14:75-83. [PMID: 25621085 PMCID: PMC4303573 DOI: 10.1016/j.aeolia.2014.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of dust and aerosol from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are heavily contaminated with lead and arsenic. Using a computational fluid dynamics model, we model dust transport from the mine tailings to the surrounding region. The model includes gaseous plume dispersion to simulate the transport of the fine aerosols, while individual particle transport is used to track the trajectories of larger particles and to monitor their deposition locations. In order to improve the accuracy of the dust transport simulations, both regional topographical features and local weather patterns have been incorporated into the model simulations. Results show that local topography and wind velocity profiles are the major factors that control deposition.
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Affiliation(s)
- Michael Stovern
- Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, United States
| | - Omar Felix
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, United States
| | - Janae Csavina
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, United States
| | - Kyle P. Rine
- Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, United States
| | - MacKenzie R. Russell
- Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, United States
| | - Robert M. Jones
- Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, United States
| | - Matt King
- Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, United States
| | - Eric A. Betterton
- Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, United States
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, United States
| | - A. Eduardo Sáez
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, United States
- Corresponding author. Address: Department of Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way, Harshbarger 108, Tucson, AZ 85721-0011, United States. Tel.: +1 520 621 5369. (A.E. Sáez)
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21
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Csavina J, Field J, Félix O, Corral-Avitia AY, Sáez AE, Betterton EA. Effect of wind speed and relative humidity on atmospheric dust concentrations in semi-arid climates. Sci Total Environ 2014; 487:82-90. [PMID: 24769193 PMCID: PMC4072227 DOI: 10.1016/j.scitotenv.2014.03.138] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/31/2014] [Accepted: 03/31/2014] [Indexed: 05/22/2023]
Abstract
Atmospheric particulate have deleterious impacts on human health. Predicting dust and aerosol emission and transport would be helpful to reduce harmful impacts but, despite numerous studies, prediction of dust events and contaminant transport in dust remains challenging. In this work, we show that relative humidity and wind speed are both determinants in atmospheric dust concentration. Observations of atmospheric dust concentrations in Green Valley, AZ, USA, and Juárez, Chihuahua, México, show that PM10 concentrations are not directly correlated with wind speed or relative humidity separately. However, selecting the data for high wind speeds (>4m/s at 10 m elevation), a definite trend is observed between dust concentration and relative humidity: dust concentration increases with relative humidity, reaching a maximum around 25% and it subsequently decreases with relative humidity. Models for dust storm forecasting may be improved by utilizing atmospheric humidity and wind speed as main drivers for dust generation and transport.
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Affiliation(s)
- Janae Csavina
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, United States
| | - Jason Field
- School of Natural Resources and the Environment, The University of Arizona, Tucson, AZ 85721, United States
| | - Omar Félix
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, United States
| | - Alba Y Corral-Avitia
- Departamento de Ciencias Básicas, Universidad Autónoma de Ciudad Juárez, 32538 Juárez, Chihuahua, Mexico
| | - A Eduardo Sáez
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, United States.
| | - Eric A Betterton
- Department of Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721, United States.
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22
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23
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Stovern M, Betterton EA, Sáez AE, Villar OIF, Rine KP, Russell MR, King M. Modeling the emission, transport and deposition of contaminated dust from a mine tailing site. Rev Environ Health 2014; 29:91-94. [PMID: 24552963 PMCID: PMC4012896 DOI: 10.1515/reveh-2014-0023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 01/17/2014] [Indexed: 06/03/2023]
Abstract
Mining operations are potential sources of airborne particulate metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, due to potential deleterious effects on human health and ecology. Dust emissions and dispersion of contaminants from the Iron King Mine tailings in Dewey-Humboldt, Arizona, a Superfund site, are currently being investigated through in situ field measurements and computational fluid dynamics modeling. These tailings are significantly contaminated with lead and arsenic with an average soil concentration of 1616 and 1420 ppm, respectively. Similar levels of these contaminants have also been measured in soil samples taken from the area surrounding the mine tailings. Using a computational fluid dynamics model, we have been able to model dust transport from the mine tailings to the surrounding region. The model includes a distributed Eulerian model to simulate fine aerosol transport and a Lagrangian approach to model fate and transport of larger particles. In order to improve the accuracy of the dust transport simulations both regional topographical features and local weather patterns have been incorporated into the model simulations.
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Affiliation(s)
- Michael Stovern
- Corresponding author: Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, USA,
| | - Eric A. Betterton
- Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, USA; and Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | - A. Eduardo Sáez
- Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA
| | | | - Kyle P. Rine
- Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
| | | | - Matt King
- Department of Atmospheric Sciences, University of Arizona, Tucson, AZ, USA
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24
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Raghav M, Shan J, Sáez AE, Ela WP. Scoping candidate minerals for stabilization of arsenic-bearing solid residuals. J Hazard Mater 2013; 263 Pt 2:525-532. [PMID: 24231323 PMCID: PMC3984437 DOI: 10.1016/j.jhazmat.2013.10.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 10/02/2013] [Accepted: 10/04/2013] [Indexed: 05/30/2023]
Abstract
Arsenic Crystallization Technology (ACT) is a potentially eco-friendly, effective technology for stabilization of arsenic-bearing solid residuals (ABSRs). The strategy is to convert ABSRs generated by water treatment facilities into minerals with a high arsenic capacity and long-term stability in mature, municipal solid waste landfills. Candidate minerals considered in this study include scorodite, arsenate hydroxyapatites, ferrous arsenates (symplesite-type minerals), tooeleite, and arsenated-schwertmannite. These minerals were evaluated as to ease of synthesis, applicability to use of iron-based ABSRs as a starting material, and arsenic leachability. The Toxicity Characteristic Leaching Procedure (TCLP) was used for preliminary assessment of candidate mineral leaching. Minerals that passed the TCLP and whose synthesis route was promising were subjected to a more aggressive leaching test using a simulated landfill leachate (SLL) solution. Scorodite and arsenate hydroxyapatites were not considered further because their synthesis conditions were not found to be favorable for general application. Tooeleite and silica-amended tooeleite showed high TCLP arsenic leaching and were also not investigated further. The synthesis process and leaching of ferrous arsenate and arsenated-schwertmannite were promising and of these, arsenated-schwertmannite was most stable during SLL testing. The latter two candidate minerals warrant synthesis optimization and more extensive testing.
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Affiliation(s)
- Madhumitha Raghav
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85641-0011, USA
| | - Jilei Shan
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85641-0011, USA
| | - A. Eduardo Sáez
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85641-0011, USA
| | - Wendell P. Ela
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85641-0011, USA
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25
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Sorooshian A, Csavina J, Shingler T, Dey S, Brechtel FJ, Sáez AE, Betterton EA. Hygroscopic and chemical properties of aerosols collected near a copper smelter: implications for public and environmental health. Environ Sci Technol 2012; 46:9473-80. [PMID: 22852879 PMCID: PMC3435440 DOI: 10.1021/es302275k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Particulate matter emissions near active copper smelters and mine tailings in the southwestern United States pose a potential threat to nearby environments owing to toxic species that can be inhaled and deposited in various regions of the body depending on the composition and size of the particles, which are linked by particle hygroscopic properties. This study reports the first simultaneous measurements of size-resolved chemical and hygroscopic properties of particles next to an active copper smelter and mine tailings by the towns of Hayden and Winkelman in southern Arizona. Size-resolved particulate matter samples were examined with inductively coupled plasma mass spectrometry, ion chromatography, and a humidified tandem differential mobility analyzer. Aerosol particles collected at the measurement site are enriched in metals and metalloids (e.g., arsenic, lead, and cadmium) and water-uptake measurements of aqueous extracts of collected samples indicate that the particle diameter range of particles most enriched with these species (0.18-0.55 μm) overlaps with the most hygroscopic mode at a relative humidity of 90% (0.10-0.32 μm). These measurements have implications for public health, microphysical effects of aerosols, and regional impacts owing to the transport and deposition of contaminated aerosol particles.
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Affiliation(s)
- Armin Sorooshian
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, United States.
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26
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Csavina J, Field J, Taylor MP, Gao S, Landázuri A, Betterton EA, Sáez AE. A review on the importance of metals and metalloids in atmospheric dust and aerosol from mining operations. Sci Total Environ 2012; 433:58-73. [PMID: 22766428 PMCID: PMC3418464 DOI: 10.1016/j.scitotenv.2012.06.013] [Citation(s) in RCA: 202] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 05/12/2012] [Accepted: 06/02/2012] [Indexed: 04/13/2023]
Abstract
Contaminants can be transported rapidly and over relatively long distances by atmospheric dust and aerosol relative to other media such as water, soil and biota; yet few studies have explicitly evaluated the environmental implications of this pathway, making it a fundamental but understudied transport mechanism. Although there are numerous natural and anthropogenic activities that can increase dust and aerosol emissions and contaminant levels in the environment, mining operations are notable with respect to the quantity of particulates generated, the global extent of area impacted, and the toxicity of contaminants associated with the emissions. Here we review (i) the environmental fate and transport of metals and metalloids in dust and aerosol from mining operations, (ii) current methodologies used to assess contaminant concentrations and particulate emissions, and (iii) the potential health and environmental risks associated with airborne contaminants from mining operations. The review evaluates future research priorities based on the available literature and suggest that there is a particular need to measure and understand the generation, fate and transport of airborne particulates from mining operations, specifically the finer particle fraction. More generally, our findings suggest that mining operations play an important but underappreciated role in the generation of contaminated atmospheric dust and aerosol and the transport of metal and metalloid contaminants, and highlight the need for further research in this area. The role of mining activities in the fate and transport of environmental contaminants may become increasingly important in the coming decades, as climate change and land use are projected to intensify, both of which can substantially increase the potential for dust emissions and transport.
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Affiliation(s)
- Janae Csavina
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
| | - Jason Field
- School of Natural Resources and the Environment, The University of Arizona, Tucson, AZ 85721
| | - Mark P. Taylor
- Environmental Science, Faculty of Science, Macquarie University, North Ryde, Sydney NSW 2109, Australia
| | - Song Gao
- Farquhar College of Arts and Sciences, Nova Southeastern University, Ft Lauderdale, FL 33314
| | - Andrea Landázuri
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
| | - Eric A. Betterton
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
| | - A. Eduardo Sáez
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
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Csavina J, Field J, Taylor MP, Gao S, Landázuri A, Betterton EA, Sáez AE. A review on the importance of metals and metalloids in atmospheric dust and aerosol from mining operations. Sci Total Environ 2012; 433:58-73. [PMID: 22766428 DOI: 10.1016/j.scititenv.2012.06.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 05/12/2012] [Accepted: 06/02/2012] [Indexed: 05/23/2023]
Abstract
Contaminants can be transported rapidly and over relatively long distances by atmospheric dust and aerosol relative to other media such as water, soil and biota; yet few studies have explicitly evaluated the environmental implications of this pathway, making it a fundamental but understudied transport mechanism. Although there are numerous natural and anthropogenic activities that can increase dust and aerosol emissions and contaminant levels in the environment, mining operations are notable with respect to the quantity of particulates generated, the global extent of area impacted, and the toxicity of contaminants associated with the emissions. Here we review (i) the environmental fate and transport of metals and metalloids in dust and aerosol from mining operations, (ii) current methodologies used to assess contaminant concentrations and particulate emissions, and (iii) the potential health and environmental risks associated with airborne contaminants from mining operations. The review evaluates future research priorities based on the available literature and suggest that there is a particular need to measure and understand the generation, fate and transport of airborne particulates from mining operations, specifically the finer particle fraction. More generally, our findings suggest that mining operations play an important but underappreciated role in the generation of contaminated atmospheric dust and aerosol and the transport of metal and metalloid contaminants, and highlight the need for further research in this area. The role of mining activities in the fate and transport of environmental contaminants may become increasingly important in the coming decades, as climate change and land use are projected to intensify, both of which can substantially increase the potential for dust emissions and transport.
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Affiliation(s)
- Janae Csavina
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, United States
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28
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Beamer PI, Luik CE, Abrell L, Campos S, Martínez ME, Sáez AE. Concentration of trichloroethylene in breast milk and household water from Nogales, Arizona. Environ Sci Technol 2012; 46:9055-61. [PMID: 22827160 PMCID: PMC3699401 DOI: 10.1021/es301380d] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The United States Environmental Protection Agency has identified quantification of trichloroethylene (TCE), an industrial solvent, in breast milk as a high priority need for risk assessment. Water and milk samples were collected from 20 households by a lactation consultant in Nogales, Arizona. Separate water samples (including tap, bottled, and vending machine) were collected for all household uses: drinking, bathing, cooking, and laundry. A risk factor questionnaire was administered. Liquid-liquid extraction with diethyl ether was followed by GC-MS for TCE quantification in water. Breast milk underwent homogenization, lipid hydrolysis, and centrifugation prior to extraction. The limit of detection was 1.5 ng/mL. TCE was detected in 7 of 20 mothers' breast milk samples. The maximum concentration was 6 ng/mL. TCE concentration in breast milk was significantly correlated with the concentration in water used for bathing (ρ = 0.59, p = 0.008). Detection of TCE in breast milk was more likely if the infant had a body mass index <14 (RR = 5.2, p = 0.02). Based on average breast milk consumption, TCE intake for 5% of the infants may exceed the proposed U.S. EPA Reference Dose. Results of this exploratory study warrant more in depth studies to understand risk of TCE exposures from breast milk intake.
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Affiliation(s)
- Paloma I Beamer
- Mel and Enid Zuckerman College of Public Health, University of Arizona, 1295 N. Martin Avenue, Tucson, Arizona 85724, United States.
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Affiliation(s)
- Mario R. Rojas
- Department of Chemical
and Environmental Engineering, The University of Arizona, Tucson, Arizona 85721, United States
| | - A. Eduardo Sáez
- Department of Chemical
and Environmental Engineering, The University of Arizona, Tucson, Arizona 85721, United States
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30
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Affiliation(s)
- Paloma I. Beamer
- Mel and Enid Zuckerman College
of Public Health, University of Arizona, 1295 N. Martin Ave, Tucson, Arizona 85724, United States
| | - Catherine E. Luik
- Mel and Enid Zuckerman College
of Public Health, University of Arizona, 1295 N. Martin Ave, Tucson, Arizona 85724, United States
| | - Leif Abrell
- Arizona Laboratory for Emerging
Contaminants, University of Arizona, 1040
E. fourth St, Rm. 611 Tucson, Arizona 85721, United States
| | - Swilma Campos
- Mariposa Community Health Center, 1852 Mastick Way, Nogales, Arizona 85621,
United States
| | - María Elena Martínez
- Moores UCSD
Cancer Center, University of California, San Diego, 3855 Health Sciences
Drive, #0901, La Jolla, California 92093, United States
| | - A. Eduardo Sáez
- Chemical and Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way,
Tucson, Arizona 85721, United States
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Rojas MR, Leung C, Whitley D, Zhu Y, Arnold RG, Sáez AE. Advanced Oxidation of Trace Organics in Water by Hydrogen Peroxide Solar Photolysis. Ind Eng Chem Res 2011. [DOI: 10.1021/ie201381j] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mario R. Rojas
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, Arizona 85721, United States
| | - Cary Leung
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, Arizona 85721, United States
| | - Daniel Whitley
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, Arizona 85721, United States
| | - Yan Zhu
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, Arizona 85721, United States
| | - Robert G. Arnold
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, Arizona 85721, United States
| | - A. Eduardo Sáez
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, Arizona 85721, United States
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Csavina J, Landázuri A, Wonaschütz A, Rine K, Rheinheimer P, Barbaris B, Conant W, Sáez AE, Betterton EA. Metal and Metalloid Contaminants in Atmospheric Aerosols from Mining Operations. Water Air Soil Pollut 2011; 221:145-157. [PMID: 23441050 PMCID: PMC3576728 DOI: 10.1007/s11270-011-0777-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Mining operations are potential sources of airborne metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, with potential deleterious effects on human health and ecology. Fine particulates such as those resulting from smelting operations may disperse more readily into the environment than coarser tailings dust. Fine particles also penetrate more deeply into the human respiratory system, and may become more bioavailable due to their high specific surface area. In this work, we report the size-fractionated chemical characterization of atmospheric aerosols sampled over a period of a year near an active mining and smelting site in Arizona. Aerosols were characterized with a 10-stage (0.054 to 18 μm aerodynamic diameter) multiple orifice uniform deposit impactor (MOUDI), a scanning mobility particle sizer (SMPS), and a total suspended particulate (TSP) collector. The MOUDI results show that arsenic and lead concentrations follow a bimodal distribution, with maxima centered at approximately 0.3 and 7.0 μm diameter. We hypothesize that the sub-micron arsenic and lead are the product of condensation and coagulation of smelting vapors. In the coarse size, contaminants are thought to originate as aeolian dust from mine tailings and other sources. Observation of ultrafine particle number concentration (SMPS) show the highest readings when the wind comes from the general direction of the smelting operations site.
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Affiliation(s)
- Janae Csavina
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
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33
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Rodríguez M, Xue J, Gouveia LM, Müller AJ, Sáez AE, Rigolini J, Grassl B. Shear rheology of anionic and zwitterionic modified polyacrylamides. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2010.10.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Arnold RG, Heyworthz J, Sáez AE, Rodriguez C, Weinstein P, Ling B, Memon S. The status of water and sanitation among Pacific Rim nations. Rev Environ Health 2011; 26:17-30. [PMID: 21714378 DOI: 10.1515/reveh.2011.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Analysis of relationships among national wealth, access to improved water supply and sanitation facilities, and population health indices suggests that the adequacy of water resources at the national level is a poor predictor of economic development--namely, that low water stress is neither necessary nor sufficient for economic development at the present state of water stress among Pacific Rim nations. Although nations differ dramatically in terms of priority provided to improved water and sanitation, there is some level of wealth (per capita GNP) at which all nations promote the development of essential environmental services. Among the Pacific Rim countries for which there are data, no nation with a per capita GNP > US$18,000 per year has failed to provide near universal access to improved water supply and sanitation. Below US$18,000/person-year, however, there are decided differences in the provision of sanitary services (improved water supply and sanitation) among nations with similar economic success. There is a fairly strong relationship between child mortality/life expectancy and access to improved sanitation, as expected from the experiences of developed nations. Here no attempt is made to produce causal relationships among these data. Failure to meet Millennium Development Goals for the extension of improved sanitation is frequently evident in nations with large rural populations. Under those circumstances, capital intensive water and sanitation facilities are infeasible, and process selection for water/wastewater treatment requires an adaptation to local conditions, the use of appropriate materials, etc., constraints that are mostly absent in the developed world. Exceptions to these general ideas exist in water-stressed parts of developed countries, where water supplies are frequently augmented by water harvesting, water reclamation/reuse, and the desalination of brackish water resources. Each of these processes involves public acceptance of water resources that are at least initially of inferior quality. Despite predictions of looming increases in water stress throughout the world, adaptation and resourcefulness generally allow us to meet water demand while pursuing rational economic development, even in the most water-stressed areas of the Pacific Rim.
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Affiliation(s)
- Robert G Arnold
- ' Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA.
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35
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Ela WP, Sedlak DL, Barlaz MA, Henry HF, Muir DCG, Swackhamer DL, Weber EJ, Arnold RG, Ferguson PL, Field JA, Furlong ET, Giesy JP, Halden RU, Henry T, Hites RA, Hornbuckle KC, Howard PH, Luthy RG, Meyer AK, Sáez AE, Vom Saal FS, Vulpe CD, Wiesner MR. Toward identifying the next generation of superfund and hazardous waste site contaminants. Environ Health Perspect 2011; 119:6-10. [PMID: 21205582 PMCID: PMC3018501 DOI: 10.1289/ehp.1002497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 10/01/2010] [Indexed: 05/02/2023]
Abstract
BACKGROUND This commentary evolved from a workshop sponsored by the National Institute of Environmental Health Sciences titled "Superfund Contaminants: The Next Generation" held in Tucson, Arizona, in August 2009. All the authors were workshop participants. OBJECTIVES Our aim was to initiate a dynamic, adaptable process for identifying contaminants of emerging concern (CECs) that are likely to be found in future hazardous waste sites, and to identify the gaps in primary research that cause uncertainty in determining future hazardous waste site contaminants. DISCUSSION Superfund-relevant CECs can be characterized by specific attributes: They are persistent, bioaccumulative, toxic, occur in large quantities, and have localized accumulation with a likelihood of exposure. Although still under development and incompletely applied, methods to quantify these attributes can assist in winnowing down the list of candidates from the universe of potential CECs. Unfortunately, significant research gaps exist in detection and quantification, environmental fate and transport, health and risk assessment, and site exploration and remediation for CECs. Addressing these gaps is prerequisite to a preventive approach to generating and managing hazardous waste sites. CONCLUSIONS A need exists for a carefully considered and orchestrated expansion of programmatic and research efforts to identify, evaluate, and manage CECs of hazardous waste site relevance, including developing an evolving list of priority CECs, intensifying the identification and monitoring of likely sites of present or future accumulation of CECs, and implementing efforts that focus on a holistic approach to prevention.
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Affiliation(s)
- Wendell P Ela
- Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, USA.
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36
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Shan J, Sáez AE, Ela WP. Evaluating the Mobility of Arsenic in Synthetic Iron-containing Solids Using a Modified Sequential Extraction Method. J Environ Eng (New York) 2010; 136:238-245. [PMID: 23459695 PMCID: PMC3584346 DOI: 10.1061/(asce)ee.1943-7870.0000136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 08/12/2009] [Indexed: 06/01/2023]
Abstract
Many water treatment technologies for arsenic removal that are used today produce arsenic-bearing residuals which are disposed in non-hazardous landfills. Previous works have established that many of these residuals will release arsenic to a much greater extent than predicted by standard regulatory leaching tests (e.g. the toxicity characteristic leaching procedure, TCLP) and, consequently, require stabilization to ensure benign behavior after disposal. In this work, a four-step sequential extraction method was developed in an effort to determine the proportion of arsenic in various phases in untreated as well as stabilized iron-based solid matrices. The solids synthesized using various potential stabilization techniques included: amorphous arsenic-iron sludge (ASL), reduced ASL via reaction with zero valent iron (RASL), amorphous ferrous arsenate (PFA), a mixture of PFA and SL (M1), crystalline ferrous arsenate (HPFA), and a mixture of HPFA and SL (M2). The overall arsenic mobility of the tested samples increased in the following order: ASL > RASL > PFA > M1 > HPFA > M2.
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Affiliation(s)
- Jilei Shan
- Los Angeles County Sanitation District, 1955 Workman Mill Road, Whittier, CA 90601
| | - A. Eduardo Sáez
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
| | - Wendell P. Ela
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
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37
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Rojas MR, Müller AJ, Sáez AE. Effect of ionic environment on the rheology of wormlike micelle solutions of mixtures of surfactants with opposite charge. J Colloid Interface Sci 2010; 342:103-9. [DOI: 10.1016/j.jcis.2009.10.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 10/05/2009] [Accepted: 10/06/2009] [Indexed: 11/25/2022]
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38
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Willinger M, Rupp E, Barbaris B, Gao S, Arnolda R, Betterton E, Sáez AE. Thermocatalytic destruction of gas-phase perchloroethylene using propane as a hydrogen source. J Hazard Mater 2009; 167:770-6. [PMID: 19217713 PMCID: PMC2693271 DOI: 10.1016/j.jhazmat.2009.01.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 01/13/2009] [Accepted: 01/14/2009] [Indexed: 05/06/2023]
Abstract
The use of propane in combination with oxygen to promote the destruction of perchloroethylene (PCE) over a platinum (Pt)/rhodium (Rh) catalyst on a cerium/zirconium oxide washcoat supported on an alumina monolith was explored. Conversions of PCE were measured in a continuous flow reactor with residence times less than 0.5s and temperatures ranging from 200 to 600 degrees C. The presence of propane was shown to increase significantly the conversion of PCE over oxygen-only conditions. Conversions close to 100% were observed at temperatures lower than 450 degrees C with 20% oxygen and 2% propane in the feed, which makes this process attractive from a practical standpoint. In the absence of oxygen, PCE conversion is even higher, but the catalyst suffers significant deactivation in less than an hour. Even though results show that oxygen competes with reactants for active sites on the catalyst, the long-term stability that oxygen confers to the catalyst makes the process an efficient alternative to PCE oxidation. A Langmuir-Hinshelwood competitive adsorption model is proposed to quantify PCE conversion.
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Affiliation(s)
- Marty Willinger
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
| | - Erik Rupp
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
| | - Brian Barbaris
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
- Department of Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721
| | - Song Gao
- Department of Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721
| | - Robert Arnolda
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
| | - Eric Betterton
- Department of Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721
| | - A. Eduardo Sáez
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
- Corresponding author. E-mail:
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39
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Gao S, Rupp E, Bell S, Willinger M, Foley T, Barbaris B, Sáez AE, Arnold RG, Betterton E. Mixed Redox Catalytic Destruction of Chlorinated Solvents in Soils and Groundwater. Ann N Y Acad Sci 2008; 1140:435-45. [PMID: 18991945 DOI: 10.1196/annals.1454.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Song Gao
- Department of Atmospheric Sciences, The University of Arizona, Tucson, Arizona, USA.
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40
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Affiliation(s)
- Muhammed Mukiibi
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona, USA
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41
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Rojas MR, Müller AJ, Sáez AE. Shear rheology and porous media flow of wormlike micelle solutions formed by mixtures of surfactants of opposite charge. J Colloid Interface Sci 2008; 326:221-6. [DOI: 10.1016/j.jcis.2008.07.022] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Revised: 07/11/2008] [Accepted: 07/11/2008] [Indexed: 11/16/2022]
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42
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Arnold RG, Teske S, Tomanek M, Engstrom J, Leung C, Zhang J, Banihani Q, Quanrud D, Ela WP, Sáez AE. Fate of Polybrominated Diphenyl Ethers during Wastewater Treatment/Polishing and Sludge Stabilization/Disposal. Ann N Y Acad Sci 2008; 1140:394-411. [DOI: 10.1196/annals.1454.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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43
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Shaw JK, Fathordoobadi S, Zelinski BJ, Ela WP, Sáez AE. Stabilization of arsenic-bearing solid residuals in polymeric matrices. J Hazard Mater 2008; 152:1115-21. [PMID: 17825487 DOI: 10.1016/j.jhazmat.2007.07.106] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 06/15/2007] [Accepted: 07/26/2007] [Indexed: 05/17/2023]
Abstract
This research investigates the use of polymeric matrices to encapsulate solid sorbents used to remove arsenic from drinking water. Arsenic-containing granular ferric oxy/hydroxide and ferric hydroxide amended alumina residuals were encapsulated in a polymeric matrix using a novel aqueous-based manufacturing process. The polymer was a blend of poly(styrene butadiene) and an epoxy resin. The polymeric waste forms produced were capable of containing more than 60 wt% of sorbent (dry basis), while keeping good mechanical properties. Arsenic leaching from encapsulated and unencapsulated residuals was evaluated using the standard toxicity characteristic leaching procedure (TCLP) and the California Waste Extraction Test (CA-WET). The results show that waste forms of the polymer-encapsulated residuals crushed for testing retain good leaching resistance when evaluated with the more aggressive CA-WET test, yielding leachate arsenic concentrations below the toxicity characteristic (TC) standard of 5mg/L. When residuals were preprocessed and encapsulated in a polymer form that avoided the size reduction required by leaching protocols, arsenic leached up to 700 times less than that from the unencapsulated residuals. Comparison of the waste form developed here with conventional cement matrices containing the same residuals show that the polymeric matrices were capable of encapsulating appreciably more material and leached arsenic at concentration levels that were more than an order of magnitude lower than cement.
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Affiliation(s)
- J K Shaw
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA
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44
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Orbay Ö, Gao S, Barbaris B, Rupp E, Sáez AE, Arnold RG, Betterton EA. Catalytic Dechlorination of Gas-phase Perchloroethylene under Mixed Redox Conditions. Appl Catal B 2008; 79:43-52. [PMID: 19234593 PMCID: PMC2390786 DOI: 10.1016/j.apcatb.2007.09.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The validity of a new method to destroy gas-phase perchloroethylene (PCE) is demonstrated at bench scale using a fixed-bed reactor that contains a Pt/Rh catalyst. Hydrogen and oxygen were simultaneously fed to the reactor together with PCE. The conversion efficiencies of PCE were sensitive to H(2)/O(2) ratio and reactor temperature. When the temperature was >/= 400 degrees C and H(2)/O(2) was >/= 2.15, PCE conversion efficiency was maintained at >/= 90%. No catalyst deactivation was observed for over two years, using only mild, convenient regeneration procedures. It is likely that PCE reduction steps precede oxidation reactions and that the importance of oxidation lies in its elimination of intermediates that would otherwise lead to catalyst poisoning. In practice, this catalytic dechlorination method holds potential for low-cost, large-scale field operation.
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Affiliation(s)
- Özer Orbay
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
| | - Song Gao
- Department of Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721
- Corresponding author. E-mail:
| | - Brian Barbaris
- Department of Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721
| | - Erik Rupp
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
| | - A. Eduardo Sáez
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
| | - Robert G. Arnold
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721
| | - Eric A. Betterton
- Department of Atmospheric Sciences, The University of Arizona, Tucson, AZ 85721
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45
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Conroy O, Sáez AE, Quanrud D, Ela W, Arnold RG. Changes in estrogen/anti-estrogen activities in ponded secondary effluent. Sci Total Environ 2007; 382:311-23. [PMID: 17543371 DOI: 10.1016/j.scitotenv.2007.04.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Revised: 04/25/2007] [Accepted: 04/25/2007] [Indexed: 05/15/2023]
Abstract
Total estrogenic activity, measured using the yeast estrogen screen reporter gene bioassay, decreased from 60 pM (equivalent 17alpha-ethinylestradiol concentration) to an estimated 1.4 pM during a 24-hour period in which secondary effluent was held in a shallow infiltration basin. Over the same period, anti-estrogenic activity, measured as an equivalent concentration of tamoxifen, increased from 35 to 260 nM, suggesting that antagonists produced during secondary effluent storage played a role in the apparent loss of estrogenic activity. Androgenic activity, measured over the same 24-hour period using the yeast androgen screen, was near or below the method detection limit (0.7 pM as testosterone). However, the same pond samples were clearly anti-androgenic. When whole-sample extracts were separated via adsorption and stepwise elution in alcohol/water solutions consisting of 20, 40 and 100% ethanol, the sum of estrogenic activities in derived fractions was always lower than the measured estrogenic activity in the whole-sample extracts. Summed anti-estrogenic activities in the same fractions, however, always exceeded values for corresponding whole-sample extracts. Results reinforce the importance of sample preparation steps (concentration of organics followed by estrogen/anti-estrogen separation) when measuring endocrine-related activities in chemically complex samples such as wastewater effluent. The potential complexity of relationships among estrogens, anti-estrogens and matrix organics suggests that additive models are of questionable validity for estimating whole-sample estrogenic activity from measurements involving sample fractions.
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Affiliation(s)
- Otakuye Conroy
- Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ 85721, USA
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46
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47
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Torres MF, González JM, Rojas MR, Müller AJ, Sáez AE, Löf D, Schillén K. Effect of ionic strength on the rheological behavior of aqueous cetyltrimethylammonium p-toluene sulfonate solutions. J Colloid Interface Sci 2007; 307:221-8. [PMID: 17118386 DOI: 10.1016/j.jcis.2006.11.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Revised: 10/31/2006] [Accepted: 11/01/2006] [Indexed: 11/22/2022]
Abstract
The influence of ionic environment on the rheological properties of aqueous cetyltrimethylammonium p-toluene sulfonate (CTAT) solutions has been studied under three different flow fields: simple shear, opposed-jets flow and porous media flow. Emphasis was placed in the experiments on a range of CTAT concentration in which wormlike micelles were formed. It is known that these solutions exhibit shear thickening in the semi-dilute regime, which has been explained in terms of the formation of shear-induced, cooperative structures involving wormlike micelles. In simple shear flow, the zero shear viscosity exhibits first an increase with salt addition followed by a decrease, while the critical shear rate for shear thickening increases sharply at low salt contents and tends to saturate at relatively high ionic strengths. The results are explained in terms of a competition between micellar growth induced by salt addition and changes in micellar flexibility caused by ionic screening effects. Dynamic light scattering results indicate that micelles grow rapidly upon salt addition but eventually achieve a constant size under static conditions. These observations suggest that the wormlike micelles continuously grow with salt addition, but, as they become more flexible due to electrostatic screening, the wormlike coils tend to adopt a more compact conformation. The trends observed in the apparent viscosities measured in porous media flows seem to confirm these hypotheses-but viscosity increases in the shear thickening region-and are magnified by micelle deformation induced by the elongational nature of the local flow in the pores. In opposed-jets flow, the solutions have a behavior that is close to Newtonian, which suggests that the range of strain rates employed makes the flow strong enough to destroy or prevent the formation of cooperative micellar structures.
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Affiliation(s)
- Miguel F Torres
- Grupo de Polímeros USB, Departamento de Ciencias de los Materiales, Universidad Simón Bolívar, Caracas 1080A, Venezuela
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Penott-Chang EK, Gouveia L, Fernández IJ, Müller AJ, Díaz-Barrios A, Sáez AE. Rheology of aqueous solutions of hydrophobically modified polyacrylamides and surfactants. Colloids Surf A Physicochem Eng Asp 2007. [DOI: 10.1016/j.colsurfa.2006.08.038] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ghosh A, Mukiibi M, Sáez AE, Ela WP. Leaching of arsenic from granular ferric hydroxide residuals under mature landfill conditions. Environ Sci Technol 2006; 40:6070-5. [PMID: 17051802 PMCID: PMC2536495 DOI: 10.1021/es060561b] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Most arsenic bearing solid residuals (ABSR) from water treatment will be disposed in nonhazardous landfills. The lack of an appropriate leaching test to predict arsenic mobilization from ABSR creates a need to evaluate the magnitude and mechanisms of arsenic release under landfill conditions. This work studies the leaching of arsenic and iron from a common ABSR, granular ferric hydroxide, in a laboratory-scale column that simulates the biological and physicochemical conditions of a mature, mixed solid waste landfill. The column operated for approximately 900 days and the mode of transport as well as chemical speciation of iron and arsenic changed with column age. Both iron and arsenic were readily mobilized under the anaerobic, reducing conditions. During the early stages of operation, most arsenic and iron leaching (80% and 65%, respectively) was associated with suspended particulate matter, and iron was lost proportionately faster than arsenic. In later stages, while the rate of iron leaching declined, the arsenic leaching rate increased greater than 7-fold. The final phase was characterized by dissolved species leaching. Future work on the development of standard batch leaching tests should take into account the dominant mobilization mechanisms identified in this work: solid associated transport, reductive sorbent dissolution, and microbially mediated arsenic reduction.
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Affiliation(s)
| | | | | | - Wendell P. Ela
- Corresponding Author: , 520-624-9323 (tel.), 520-621-6048 (fax)
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Ghosh A, Sáez AE, Ela W. Effect of pH, competitive anions and NOM on the leaching of arsenic from solid residuals. Sci Total Environ 2006; 363:46-59. [PMID: 16239021 DOI: 10.1016/j.scitotenv.2005.06.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Accepted: 06/16/2005] [Indexed: 05/04/2023]
Abstract
Implementation of the new arsenic MCL in 2006 will lead to the generation of an estimated 6 million pounds of arsenic-bearing solid residuals (ABSRs) every year, which will be disposed predominantly in non-hazardous landfills. The Toxicity Characteristic Leaching Procedure (TCLP) is typically used to assess whether a waste is hazardous and most solid residuals pass the TCLP. However, recent research shows the TCLP significantly underestimates arsenic mobilization in landfills. A variety of compositional dissimilarities between landfill leachates and the TCLP extractant solution likely play a role. Among the abiotic factors likely to play a key role in arsenic remobilization/leaching from solid sorbents are pH, and the concentrations of natural organic matter (NOM) and anions like phosphate, bicarbonate, sulfate and silicate. This study evaluates the desorption of arsenic from actual treatment sorbents, activated alumina (AA) and granular ferric hydroxide (GFH), which are representative of those predicted for use in arsenic removal processes, and as a function of the specific range of pH and concentrations of the competitive anions and NOM found in landfills. The influence of pH is much more significant than that of competing anions or NOM. An increase in one unit of pH may increase the fraction of arsenic leached by 3-4 times. NOM and phosphate replace arsenic from sorbent surface sites up to three orders of magnitude more than bicarbonate, sulfate and silicate, on a per mole basis. Effects of anions are neither additive nor purely competitive. Leaching tests, which compare the fraction of arsenic mobilized by the TCLP vis-a-vis an actual or more realistic synthetic landfill leachate, indicate that higher pH, and greater concentrations of anions and NOM are all factors, but of varying significance, in causing higher extraction in landfill and synthetic leachates than the TCLP.
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Affiliation(s)
- Amlan Ghosh
- Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, United States.
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